Document management services and other services often utilize concordances provide an index of terms and phrases specified in documents and other resources provided by these services. For instance, in response to a user request to identify documents that include certain terms and phrases, a document management service may evaluate the concordance to identify any documents that satisfy the request. However, using concordances to index terms and phrases in documents and other resources present various issues. For instance, it can be complex and resource-intensive to prevent use of a concordance from revealing sensitive information inadvertently to entities not authorized to access certain documents or other resources provided by these services.